Suboptimal quality of care and soaring medical costs have been perennial problems in the U.S. healthcare system. Measures that rationalize clinical practices, such as formal clinical guidelines and computerized decision support tools, were developed to improve quality of care and control costs. The prominence of rationalizing processes in healthcare has been growing exponentially. However, empirical evidence shows that rationalizing processes are not consistently utilized in clinical practice, and their effects on physician behavior are variable. It has been suggested that rationalizing processes impinge on physician autonomy and hence provoke resistance. Why is physician autonomy negatively affected by rationalizing processes? Do all physicians feel the same about rationalizing processes? Do different types of rationalizing processes influence physician autonomy to the same degree? This project proposes to address these issues using quantitative data from the Community Track Study (CTS) Physician Survey and qualitative interviews with 36 physicians. The proposed study seeks to examine if the effects of rationalizing processes on physician autonomy vary by types of rationalizing processes, and if different types of rationalizing processes influence physician autonomy to different degrees. It also aims to understand how physicians' conceptions of professional work and autonomy influence their attitudes towards and practices of rationalizing processes. The candidate proposes that physicians' conceptions of professional work and autonomy, which are derived from core values in medical professionalism, influence physicians' attitudes towards rationalization of clinical practices, and thereby impact upon their practices of rationalizing processes. Contingent upon their professional training and socialization and differential positions within the profession and healthcare system, physicians might adopt different conceptions and develop different attitudes and adoption behavior of rationalizing processes. Types of rationalizing processes might also have differential effects on how attitudes towards rationalizing processes influence adoption behavior.